This method is described in ISO 8256 and ASTM D 1822 with two possible methods.
Method A uses a dumbbell specimen that is placed in one end of the clamping fixture. A yoke is fixed to the other end. During the test, the pendulum hammer takes the yoke with it and loads the specimen in the tensile direction until break. Some of the potential impact energy of the pendulum hammer is used to set the yoke in motion, and some of this impact energy is used by the deformation of the specimen. Test results from tests with the same pendulum-yoke combination can be compared directly.
The standards define correction methods for various combinations. These enable approximate comparability.